Fixed Product comonad snippets

src/content/3.7/code/haskell/snippet08.hs

@@ -1 +1 @@
-data Product e a = P e a deriving Functor
+data Product e a = Prod e a deriving Functor

src/content/3.7/code/haskell/snippet09.hs

@@ -1,4 +1,4 @@
 (=>=) :: (Product e a -> b) -> (Product e b -> c) -> (Product e a -> c)
-f =>= g = \(P e a) -> let b = f (P e a)
+f =>= g = \(Prod e a) -> let b = f (Prod e a)
-                          c = g (P e b) 
+                          c = g (Prod e b) 
                       in c

src/content/3.7/code/haskell/snippet10.hs

@@ -1 +1 @@
-extract (P e a) = a
+extract (Prod e a) = a

src/content/3.7/code/haskell/snippet32.hs

@@ -1 +1 @@
-counit (Product (Reader f, s)) = f s
+counit (Prod (Reader f) s)) = f s

src/content/3.7/code/haskell/snippet34.hs

@@ -1 +1,2 @@
-unit a = Reader (\s -> Product (a, s))
+unit :: a -> Reader s (Product a s)
+unit a = Reader (\s -> Prod a s)